1. Field
The disclosed and claimed concept relates generally to electronic devices and, more particularly, to a method for controlling an autofocus mechanism related to a camera module incorporated into a portable electronic device in order to reduce continuous autofocus power consumption.
2. Background
Numerous types of handheld electronic devices are known. Examples of such handheld electronic devices include, for instance, personal data assistants (PDAs), handheld computers, two-way pagers, cellular telephones, and the like. Many handheld electronic devices also feature wireless communication capability, although many such handheld electronic devices are stand-alone devices that are functional without communication with other devices.
Some handheld electronic devices and other electronic devices employ small cameras that can take photographs that are then stored on the electronic device. Such cameras typically are digital cameras that comprise a camera lens, a sensor, and a processor system, which may be manufactured and sold as a modular unit. In contrast to an analog camera that records an image chemically or physically on film or another medium, a digital camera processes images electronically. Typically, the sensor receives light through the camera lens and generates an image signal as a function of the image received by the sensor. The sensor provides the image signal to an embedded program stored and executed on the processor system in order to process the image in various ways.
Such cameras typically include an autofocus function that automatically adjusts the camera lens to ensure that the subject of a picture is properly focused. Such autofocus function generally causes a rather significant delay between when a camera button is “clicked” by a user desiring to capture an image and when the image is actually captured by the device. Such delay is caused by the time required for auto-focusing (generally 1 second for a full scan) of the image. Frequently such delay is undesirable to a user and may cause a particular image to be wholly or partially missed.
One potential approach for reducing such delay is to allow the auto-focus system to continually run an autofocus routine, whereby the lens may be moved substantially continuously to the current “best” focus position. Such an approach may draw a significant amount of power, however, and such power draw is generally undesirable in such a handheld electronic device where battery size is generally sought to be reduced and battery life increased.